1. Technical Field
The present invention relates to an image blur correction device (image stabilization device) mounted in, e.g., a lens body tube or a shutter unit in a digital camera, and to an imaging lens unit and a camera unit including this image blur correction device, and more particularly to a small and thin image blur correction device (image stabilization device) applied to a camera unit mounted in a personal digital assistance such as a mobile phone, and to an imaging lens unit and a camera unit.
2. Description of the Related Art
As a conventional image blur correction device (image stabilization device), there is known an image blur correction device including: a substantially rectangular base having an opening portion at the center; a first guide shaft provided on a front surface of the base; a first movable member supported to be reciprocable along the first guide shaft; a second guide shaft directed to a 90-degree direction with respect to the first guide shaft and provided on a front surface of the first movable member; a second movable member supported to be reciprocable along the second guide shaft and configured to hold a lens; a first drive device configured to reciprocate the first movable member and the second movable member together in a direction of the first guide shaft; and a second drive device configured to reciprocate the second movable member in a direction of the second guide shaft, the image blur correction device adopting a voice coil motor including a coil and a magnet as each of the first drive device and the second drive device (see, e.g., Japanese Unexamined Patent Application Publication No. 2007-286318, U.S. Patent Application Publication No. 2007/0242938A1, and others).
However, this device adopts a double configuration that the first movable member and the second movable member are aligned in an optical axis direction, thus leading to an increase in size of the device in the optical axis direction.
Further, although the second drive device drives the second movable member alone, the first drive device must drive not only the first movable member but also the second movable member and the second guide shaft at the same time, larger drive force must be generated as compared with a situation where the first movable member alone is driven, thereby resulting in an increase in size of the first drive device. Furthermore, since a drive load of the first drive device is different from a drive load of the second drive device, drive control for positioning the les within a plane vertical to the optical axis is not easy.
Moreover, as another image blur correction device (image stabilization device), there is known an image blur correction device including: a substantially rectangular base having an opening portion; four elastic support members (wires) that are implanted in four corners of a front surface of the base and extend in an optical axis direction; a movable member coupled with ends of the four elastic support member to hold a lens; a first magnet and a first yoke provided to a movable member; a second magnet and a second yoke provided to the movable member; and a substantially rectangular fixed frame that is fixed to a member different from the base and arranged in front of the movable member to hold a first coil and a second coil, the first magnet, the first yoke, and the first coil constituting first driving means, the second magnet, the second yoke, and the second coil constituting second driving means, the first driving means being configured to drive the movable member in a first direction vertical to the optical axis, the second driving means being configured to drive the movable member in a second direction vertical to the optical axis and the first direction (see, e.g., Japanese Unexamined Patent Application Publication No. 2008-64846).
However, in this device, since the movable member is supported on the base by using the four elastic support members (the wires) extending in the optical axis direction and the fixed frame configured to hold the coils is supported in front of the movable member by the other member, the size of the device increases in the optical axis direction, and coupling portions of the four elastic support members are coupled rigidly rather than coupled in a link state, whereby the movable member (the lens) may be possibly not only moved in a plane direction vertical to the optical axis but also inclined with respect to the optical axis. Additionally, although the base is coupled with the movable member, since the fixed frame holding the coils is not integrally coupled, the image blur correction device cannot be configured as a module, its handling is inconvenient, the first magnet and the second magnet of the movable member and the first coil and the second coil of the fixed frame cannot be positioned, respectively, with one member (e.g., the base) being determined as a reference, and assembling the device is troublesome. Further, since (the first magnet and the first yoke of) the first driving means and (the second magnet and the second yoke of) the second driving means are arranged on one side of the movable member alone with respect to the lens, the first driving means and the second driving means exercise drive force to one side of the movable member alone rather than both sides of the lens in a symmetric manner, and they tend to facilitate inclination of the movable member, i.e., inclination of the lens.
Furthermore, as still another image blur correction device (image stabilization device), as shown in FIG. 19, there is known an image blur correction device including: a base 1; a movable member 2 holding a lens G; a plurality of driving means (a coil 3 and others) fixed to the movable member 2; a flexible wiring board 4 including a wiring portion 4a arranged along a front surface of the movable member 2 to configure wirings with respect to, e.g., the coil 3; and others, soldering portions 4b connecting lead portions of the coil 3 being provided on the front surface of the movable member 2 where the lens G is exposed (see, e.g., Japanese Patent Publication No. 3740475).
However, since the soldering portions 4b are assured on the front surface of the movable member 2, a reduction in size (a reduction in width) of the movable member and others are difficult. Moreover, since the soldering portions 4b and the lens G are close to each other, heat of a soldering iron is transferred to the movable member 2 or the lens G at the time of a soldering operation, and the movable member 2 or the lens G may be possibly thermally broken or damaged.